1. Field of the Invention
The present invention relates to a microphone device, and more particularly, to an integrated micro electro-mechanical system (MEMS).
2. Description of the Prior Art
The micro electro-mechanical system (MEMS) integrates various electronic, electrical engineering and mechanical functions into a microelement via semiconductor manufacturing processes. Compared with microphones assembled using traditional methods, the MEMS microphone has the advantages of smaller size, lower power consumption and better resistance against environmental disturbances such as temperature variations, shock and electromagnetic interference.
Please refer to FIG. 1, which is a diagram illustrating a conventional MEMS microphone 100. The conventional MEMS microphone 100 includes a carrier board 20, a silicon substrate 30, a membrane 40, a back plate 50 and an application-specific IC (ASIC) 60, wherein the silicon substrate 30, membrane 40, back plate 50 and application-specific IC (ASIC) 60 form a MEMS unit. The membrane 40 is a flexible membrane, which vibrates in response to sound pressure to generate minor variations, causing the dynamical shifts of its position. The capacitance of the MEMS microphone 100 will vary accordingly. The silicon substrate 30 and the ASIC 60 are both configured on the carrier board 20. The ASIC 60 provides regular bias voltages for operating the MEMS normally, and amplifies signals to be output.
Some noise may be present in the MEMS due to the ASIC 60. This seriously interferes with the MEMS microphone 100, and performance will be lowered. Therefore, there is a need to provide a new capacitive microphone to solve the aforementioned problems.